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Biomedical subjects

R Attewell

Publications and source records attributed to R Attewell.

51 records · Page 3Linked to original sources
PubMed1988

Biological effects in a chemical factory with mutagenic exposure. II. Analysis of unscheduled DNA synthesis and adenosine diphosphate ribosyl transferase, epoxide hydrolase, and glutathione transferase in resting mononuclear leukocytes.

A chemical plant, where an increased number of non-Hodgkin's lymphomas and myelomas had been observed, was monitored for genotoxic effects occurring in peripheral mononuclear leukocyte samples from 76 exposed workers. Biochemical markers sensitive to DNA repair and drug metabolism were used as the indicators of genotoxic risk. Unscheduled DNA synthesis (UDS) and covalent binding induced by N-acetoxy-N-acetyl-2-aminofluorene (NA-AAF) and constitutive and gamma ray induced adenosine diphosphate ribosyl transferase (ADPRT) activities were highly and significantly elevated over the corresponding values for a control group of 48 postal workers. Microsomal and soluble epoxide hydrolases and glutathione transferase activities directed towards trans-stilbene oxide and 1-chloro-2,4-dinitrobenzene were not significantly altered in the exposed group. The exposure in this factory was complex, involving over 100 chemicals including several well known carcinogens. However, no apparent significant associations to exposure could be established.

Acetoxyacetylaminofluorene↗
PubMed1988

Biological effects in a chemical factory with mutagenic exposure. III. Urinary mutagenicity and thioether excretion.

Eighty-five workers in a chemical plant, in which there was an increased frequency of B-lymphocyte tumours (myelomas and lymphomas) and lung cancer, did not excrete higher amounts of thioethers in urine than 48 control subjects. The chemically exposed workers had, however, a higher excretion of thioethers in urine during shift compared to an exposure-free period. The bacterial fluctuation test showed a statistically significantly increased mutagenic activity for E. coli Wp2 uvrA, but not for Salmonella TA98, in the urine of the exposed workers compared with the controls. However, no difference in excretion was found in the chemical workers between work and an exposure free-period. Further, no association of thioether or mutagen excretion with any specific chemical exposure (e.g. ethylene oxide and formaldehyde) in the plant could firmly be established.

Adult↗
PubMed1988

Relation between lead and cadmium in blood and the involuntary smoking of children.

The blood lead (PbB) and blood cadmium (CdB) levels, as well as the parental smoking habits, of 133 children aged 4 to 11 years were studied. The children were from a town with a lead smeltery and a surrounding rural area. There was a significant association between the higher PbB levels of the children and involuntary (parental) smoking in the home. The CdB levels of the children were not affected by parental smoking habits. The children whose parents did not smoke at home had lower PbB values than those with one smoking parent. These children, in turn, had lower levels than children with two smoking parents. Mothers who smoked had a greater impact than fathers who smoked. There was also a dose-response relationship between the amount of tobacco smoked by the mother and the PbB level of the child. The PbB value was higher for the children living near industrial lead emissions than for children from the rural area. The association between PbB level and involuntary smoking is probably not due to inhalation of lead originating from tobacco smoke. A small airways disease affecting the absorption of inhaled lead particles is proposed as an explanation.

Cadmium↗
PubMed1987

The staging of soft-tissue sarcomas.

We have assessed the ability of the American Joint Committee System, the Hajdu and the Surgical Staging System to separate different prognostic groups of patients with soft-tissue sarcoma. There were 122 patients with nonmetastatic tumours of the locomotor system. All were operated on with a wide, or radical, surgical margin. None of the staging systems could identify more than two groups with significantly different overall survival. A plea is made for the use of statistical multivariate analysis of prognostic factors when constructing staging systems for soft-tissue sarcoma.

Adolescent↗
PubMed1987

Survival in soft tissue sarcoma. Prognostic variables identified by multivariate analysis.

The prognostic influence of 15 separate factors on local recurrence and survival was analyzed in 144 patients with highly malignant (histologic Grades III and IV) soft tissue sarcoma of the locomotor system. The minimum follow-up time was 6 years, or until death. Three factors, marginal excision, tumor necrosis, and extracompartmental tumor location were identified as risk factors for local recurrence. Five factors, local recurrence, Grade IV, male sex, tumor necrosis, and increasing tumor size were associated with decreased life expectancy.

Adolescent↗
PubMed1986

Mortality and cancer morbidity among workers in a chemical factory.

A retrospective cohort study was performed on a group of 664 male workers employed for at least one month during the period 1942-1979 in a chemical factory. Both established and suspected carcinogens had been handled in the plant, primarily piperazine, but also urethane, ethylene oxide, formaldehyde, and organic solvents. A significantly increased mortality, compared with the regional death rate, was observed in the cohort. The increase was mainly due to violent deaths and cardiovascular diseases. No rise in death rates was observed for asthma, bronchitis or emphysema, in spite of other evidence of a high risk of occupational asthma, due to exposure to piperazine. A statistically significant increase in cancer morbidity was observed for malignant lymphoma/myelomatosis when an induction latency time of at least 10 years was used. Furthermore, an increase in bronchial cancer was noted, but it was statistically significant only when an induction-latency time of at least 15 years was used. A case-referent study within the cohort did not reveal any significant association between any specific chemical exposure and cancer morbidity.

Adult↗
PubMedDate not supplied

Prognostic factors in head and neck cancer: histologic grading, DNA ploidy, and nodal status.

Histopathologic malignancy score and DNA ploidy were investigated as prognostic factors for 72 cases of squamous cell carcinoma of the head and neck (HNSCC). The malignancy grading was based upon four different morphologic characteristics for the tumor cell population and four characteristics for the tumor-host relationship. DNA ploidy was determined through flow cytometry on fresh-frozen tumor samples. The median malignancy score was 20, with 71% of the tumors scoring less than 20 being diploid and 68% of the tumors scoring greater than or equal to 20 being nondiploid (p = 0.003). Univariate analysis revealed that tumors scoring less than 20 and diploid tumors had a significantly higher proportion of complete response and better survival as compared to tumors scoring greater than or equal to 20 and nondiploid tumors, respectively. There was a tendency toward better survival among patients without regional metastasis (N0) as compared with patients with regional spread (N+), whereas the other single factors, patient age, clinical stage, histologic grade, and tumor size did not correlate with prognosis. In N+ patients both malignancy score and DNA ploidy were predictive for survival, whereas in N0 patients only malignancy score was related to prognosis. A multivariate analysis showed that the combination of malignancy score and nodal status were the strongest predictors for survival. DNA ploidy did not contribute further information in this test, due to its close relation with the histopathologic malignancy score.

Adult↗
PubMedDate not supplied

Emergency department presentation of renal dialysis patients: indications for EMS transport directly to dialysis centers.

To determine the pattern of emergency department (ED) utilization by renal dialysis (RD) patients, a prospective study was conducted of dialysis patients presenting to the ED of a regional dialysis center. The most common presenting complaints were shortness of breath (SOB), chest pain, abdominal pain, and vomiting; the most common diagnoses were congestive heart failure, chest wall pain, and electrolyte abnormalities. Interventional dialysis (ID), defined as emergent dialysis required to treat the patient's presenting complaint, was required for 30 patients, with the most common presenting complaints of these patients being shortness of breath, weakness, and chest pain. Only SOB was statistically significant in predicting the need for ID (P less than 0.001), with a positive predictive value of 0.63 and a negative predictive value of 0.85. Prehospital implications of these data suggest that RD patients with a chief complaint of SOB should be transported directly to a facility capable of dialysis on an emergent basis.

Emergencies↗
PubMedDate not supplied

Decreasing blood lead in Swedish children, 1978-1988.

The geometric mean of the blood lead concentrations in 1,781 samples obtained from children during 1978 to 1988 was 46.9 micrograms/l (0.23 mumol/l) (range: 14-250 micrograms/l [0.07-1.2 mumol/l]). There was a significant (p less than .001) decrease in blood lead concentrations of 7%/y in rural and urban areas. In 134 children who were sampled twice, the decrease over 2-y periods was 14%. The striking decrease in blood lead levels is most likely the result of a reduction of lead additives in motor fuel during this period.

Adolescent↗
PubMedDate not supplied

Status of mercury and selenium in dental personnel: impact of amalgam work and own fillings.

Urinary mercury (U-Hg) and plasma mercury (P-Hg) levels were higher in 244 dental personnel than in 81 matched referents (U-Hg: 1.8 and 1.1 mumol/mol creatinine, respectively; p less than .001; P-Hg: 6.7 and 6.2 nmol/l, respectively; p = .03). The amalgam in the mouth influenced mercury levels in whole blood (B-Hg), plasma, and urine. The association was nonlinear: the more amalgam, the larger the relative increase in mercury levels. The number of amalgam surfaces accounted for more of the variance in blood and urine mercury levels than did the number of fillings (e.g., U-Hg: 44% and 36%, respectively). The estimated increases in mercury level with rising amalgam load were 3.0%, 2.0%, and 0.8% per filled surface for U-Hg, P-Hg, and B-Hg, respectively (p less than .0001 in all cases). The impact of occupational exposure on U-Hg in the dental personnel corresponded to approximately 19 amalgam surfaces. Ceramo metallic restorations were associated with higher (31%) U-Hg.

Adult↗
PubMedDate not supplied

Kinetics of mercury in blood and urine after brief occupational exposure.

The decrease in mercury (Hg) levels in whole blood (B), plasma (P), erythrocytes (Ery), and urine (U) was investigated in nine men after 3 d of intense (greater than 100 micrograms/m3) exposure to metallic Hg vapor. In a model in which common half-times for all subjects were used, the best fit for B-Hg was obtained with half-times of 3.1 d for a fast phase and 18 d for a slow phase. P-Hg seemed to decay more rapidly than Ery-Hg. Peak U-Hg (morning, creatinine-corrected samples) was not observed until 2-3 wk after exposure. Thereafter, the median half-time was 40 d (assuming individual one-compartment models). In a model for which common half-times were used, the point estimates were 59 d for a one-compartment model and 28 and 141 d for a two-compartment model. The fractions of the fast phases (i.e., two-compartment models with common half-times) were 80% for B-Hg and 84% for U-Hg.

Environmental Monitoring↗
PubMedDate not supplied

Exposure to environmental tobacco smoke in the household and urinary cotinine excretion, heavy metals retention, and lung function.

The relationship between urinary levels of cotinine (U-cotinine) and arsenic (U-As), blood levels of cadmium (B-Cd), blood levels of lead (B-Pb), lung function, and questionnaire data on smoking habits were studied in 107 parents and their 46 children (7-10 y of age). There was a statistically significant relationship between the reported amount of tobacco smoked and U-cotinine levels. Nonsmokers who were married to persons who smoked had three times higher U-cotinine levels than nonsmokers whose spouses did not smoke. There was a significant association between the number of parents who smoked in the family and the U-cotinine levels of children. If only one parent smoked, maternal smoking was of greater importance than paternal smoking. There was also an association between U-cotinine and B-Cd. A study of lung function in the children revealed that vital capacity and functional residual capacity (corrected for sex, age, and height) increased as the number of parents who smoked increased. Therefore, the present study showed that (1) U-cotinine was a useful index of active smoking and environmental tobacco smoke exposure in adults and children, (2) U-cotinine was associated with the blood concentration of cadmium, and (3) environmental tobacco smoke exposure was associated with changes in lung function of children.

Adult↗
PubMedDate not supplied

In vivo measurements of lead in bone in long-term exposed lead smelter workers.

In-vivo measurements of lead concentrations in calcaneus (mainly trabecular bone) and tibia (mainly cortical bone) were performed by x-ray fluorescence (XRF) in 70 active and 30 retired lead smelter workers who had long-term exposure to lead. Comparison was made with 31 active and 10 retired truck assembly workers who had no known occupational exposure to lead. After physical examination, all participants provided blood and urine samples and answered a computerized questionnaire. Since 1950, blood lead has been determined repeatedly in lead workers at the smelter, which made it possible to calculate a time-integrated blood lead index for each worker. Lead concentrations in blood, urine, calcaneus, and tibia in active and retired lead workers were significantly higher than in the corresponding control groups (p < .001). The highest bone lead concentrations were found among retired lead workers (p < .001), which was the result of considerably higher lead exposure during 1940 to 1960. Lead concentrations in calcaneus in active lead workers were significantly higher than in tibia when expressed in ug of lead per gram of bone mineral, which suggests a quicker absorption over time in this mainly trabecular bone. The estimated biological half-times were 16 y in calcaneus (95% confidence interval [95% CI] = 11-29 y) and 27 y in tibia (95% CI = 16-98 y). A strong positive correlation was found between lead concentrations in calcaneus and tibia for all lead workers (r = 0.54; p < .001). A strong positive correlation was also found between the bone lead concentrations and the cumulative blood lead index. Blood lead, at the time of study, correlated well with bone lead concentrations in retired--but not in active--workers, reflecting the importance of the endogenous (skeletal) lead exposure. The findings in this study indicate that bone lead measurements by XRF can give a good index of long-term lead exposure. Tibia measurements offer a higher precision than calcaneus measurements. The method is of particular interest in epidemiologic studies of adverse health effects caused by long-term lead exposure.

Adult↗